Electric resistance element.



UNITED srAT s PATENT OEEIOE.

ALBERT'L. MARSH, OF LAKE BLUFF, ILLINOIS, ASSIGNOR TO .THE HOSKINS COMPANY, OF CHICAGO, ILL NOIS, A CORPORATION OF ILLINOIS.

Specification of Letters Patent.

Patented May 14, 1907;

Application filed January 17I 1907. Serial No. 352.690-

To all whom it Inay concern."

Be it known that I, ALBERT L. MARSH, a citizen of the United States, residing at Lake Bluff, in the county ofLake and State of Illinois, have invented a new and useful Improvement in Electric Resistance Elements, of which the following is a specification.

My object is tO'pIOVldG, as an improved electric resistance material, a metal which has the property 'of being particularly low in electric conductivity, has a melting-point exceeding that of pure copper, and may be drawn or otherwise shaped to form particularly durable, efficient, and desirable strips, strands, or filaments suitable for use in the various connections where electric resist ances are desirable.

I have discovered that the metal vanadium has the properties of being very low in electric conductivity, and very-infusible, and that when-mixed'with nickel or cobalt it forms an alloy having the additional properties of being tough and sufficiently ductile to permit drawin or shaping it into wire or strip form to ren er it convenient for use as an-electric resistance element.

I have found that an alloy consisting of about efiighty-five per cent. nickel cobalt and about teen per cent. commercially pure vanadium may be drawn into a fine Wire and annealed, producing a tough metal having a melting-point exceeding that of pure copper and with an electric resistance approximating fifty times that of pure copper. Its temperature coefficient is particularly low, that of the alloy containing fourteen per cent. of vanadium, being. positive about .000345 for each degree C.- betWeen 20 and 120; it does not become crystalline and brittle under heating and cooling; it resists oxidation at ordinary temperature and up to red heat,

I conditions.

and it keeps a polish under all atmospheric In practice I prefer, mainly for commerclal reasons, to form the. alloy of preferably less than fifteen per cent. vanadium and morethan eighty per cent. nickel. Variations in the relative proportions of the metals afiect more or less the variations in strength, dura blhty, and resistivity of the alloy.

It may be stated, for example, that a metal alloy consisting of 14.2 er cent. vanadium'jand 85.8 per cent. nicke drawn into a wire .40 mm. in diameter has a resistance approximating 3 ohms er foot. The speci ,0 resistance of this a1 0y is about 129 microhms, or more than seventy times the resistance of copper.

Whilelfor most purposes alloys of nickel and vanadium containing less than twenty per cent. of vanadium are most practical because of their ductility, all other suitable proportions of these metals are Within my invention of the alloy. I

In its broadest sense, however, my invention is not limited to analloy of these metals. Cobalt is suitable for my urpose as the equivalent of nickel; and w ere I mention in the'claims a metal having the properties of nickel and cobalt, I Wish to,desi nate only the metals nickel and cobalt wfiich have properties that are the same for my purpose, but which cannot be classed under any single term of which I am aware.

What I claim as new anddesire to secure by Letters Patent is H 1. An electric resistance element comprisng a strip, strand or filament containing vanadium.

2. An electric resistance element comprising'a strip, strand or filament formed of an alloy of vanadium and a'metal having the ALBERT LfMARsH.

In the presence of-- J. R. SP NoE, p C. W SHBURNE. 

